Control for electric hoists



Oct. 19, 1943. c. J. MANNEY 2,332,390

CONTROL FOR ELECTRIC HOISTS III / INVE/I-OR I Cdf/ef AVU/Mey Oct. 19, 1943. c. J. MANNEY 2,332,390

CONTROL FOR ELECTRIC HOISTS Filed May '7, 1942 2 Sheets-Shea?I 2 Patented Oct. 19, 1943 CONTROL FOR ELECTRIC HOISTS Charles J. Manney, Kenmore, N. Y., assignor to Columbus McKinnon Chain Corporation, Tonawanda, N. Y., a corporation ot New York Application May 7, 1942, Serial No'. 442,117

21 Claims.

The principal object of my invention has been to provide a control for electric hoists in which a motor, having two separate windings, is employed, and by which the motor and hoist may be operated at twov dier'ent speeds in either direction.

Another object has been to provide a control eunit for governing the hoisting and lowering circuits of the hoist, such circuits being so interconnected that they are electrically interlocked against simultaneous operation.

Moreover, my invention provides a two-speed control unit so designed that, for instance, the fast-speed group of contacts shall be electrically interlocked when the slow group of contacts are engaged, whereby it shall be impossible to pass current through the slow-speed and the fastspeed circuits of the motor at the same time.

Another object of my invention has been to provide control units so interconnected that the slow-speed circuit will be prepared for energize.- tion before the hoisting or lowering circuits are energized, thereby synchronizing the Aenergize.- tion of the motor with the release of the magnetic brake of the hoist.

A further object has been to provide the hoisti ing and lowering contactor unit of my invention with mechanical interlocking means, whereby the closing of both hoisting and lowering circuits at the same time by impact shall be impossible.

Furthermore, it has been an object to provide a push-button unit having contacts so arranged in overlapping relation that the fast-speed circuit will be prepared and ready for energization before the slow-speed circuit is broken or vice versa, whereby the magnetic brake of the motor will not be released during the change from one speed to another.

Moreover, the contacts of my push-button unit are so arranged that they engage in a sequential manner, in order to prevent the release of the brake before the motor is energized, thus preventing the load from overhauling the motor.

The above objects and advantages have been accomplished by the invention herein shown and described.

Fig. 1 shows a diagram of a control circuit embodying my invention.

Figs. 2 and 3 show fragmentary views indicating various positions of one of the buttons of the push-button unit.

Fig. 4 is an end View of the hoisting and lowering contactor unit.

Fig. 5 is a fragmentary end elevation of this contactor unit.

For clearness of illustration, no mechanical details are shown except the mechanical interlock on the hoisting and lowering contactor. A diagrammatic representation ot the various parts of the switches and push-button unit is shown for clearness of illustration, and because of the fact that various different and well-known arrangements of contact points may be employed.

Referring to Fig, 1, I0 represents in general the contactor governing the slow-speed and fastspeed circuits of the motor, and Il represents the contactor governing the hoisting and lowering circuits of the motor. These contactors are, in the commercial structure, mounted within the casing of the hoist and connected as hereinafter described. The motor is represented at I2, and this motor is provided with two separate windings each giving a different speed of rotation. Obviously, this motor is carried by the hoist, and the windings thereof are connected to the contactors I0 and H and to the push-button unit i3 by suitable leads as will hereinafter be described.

The motor employed in my invention is preferably of the three-phase type and all of the circuits herein shown and described are, therefore, of a nature to conduct the three-phase current thereto which is supplied from a suitable source over leads I4, l5 and i6.

The contactor H is provided with a group of hoisting contact points 2li-30, 2I-3|, and 22 32, and with a group of lowering contact points 23-33, 24--34, and 25-35. Jumpers 26, 21 and 28 connect the points 20 and 23, 2| and 24, and 25 and 22 together, respectively.

The stationary contact points of the hoisting group of the contactor H are provided with a movable member 36, and the stationary contact points of the lowering group of this contactor are also provided with a movable member 31. The movable member 36 of the hoisting group is provided with Contact arms 40, 4I and 42 for engagement with, and closing of, opposite points 20 and 30, 2l and 3|, and 22 and 32. Likewise. the movable member 31 of the lowering group of points has contact arms 43, 44 and 45 for engagement with, and closing of, opposite contacts 33 and 23, 34 and 24, and 35 and 25, respectively.

The stationary points just above described in both groups of points of the contactor ll are normally open. The hoisting group is also provided with contact points 46 and 41, normally closed by a contact arm 50 carried by the movable member 36. In like manner, the lowering group in this contactor is also provided with stationary contact points 5I and 52 which are normally closed by means of a contact arm 53 which is carried by the movable member 31. As is customary in devices of this nature, the movable members 36 and 31 may be normally held in the positions shown by means of gravity or a suitable spring (not shown), and a solenoid 54 is provided for causing the actuation of the movable member 36. A similar solenoid 55 is provided for causing the actuation of the movable member 31.

The contactor is provided with a slow-speef'l group of oppositely-arranged stationary contact points B-51, 60-6I, and 62--63. A movable member 64 having contact arms 65, 66 and 61 serves to connect the groups of stationary points just above mentioned. In like manner, a fastspeed group of contact points -1|, 12-13, and 14--15 is also provided on this contactor. Points 51, 6| and 63 of the slow-speed group are connected, respectively, to points 10, 12 and 14 of the fast-speed group by means of jumpers 86, 81 and 88, respectively.

A movable member 16 carrying contact arms 80, 8| and 82 serves to close the group of points 101|`, 'l2-13, and 14-15, respectively.

The slow-speed group of points of the contactor |0 also includes stationary points 83 and 84 which are normally closed by means of an arm 85 carried by the movable member G4. Likewise, the fast-speed group includes stationary points 90 and 9| normally closed by means of an arm 92 carried by the movable member 16. The movable members 64 and 16 of the contactor I0 may be held in the positions shown in the drawings by means of gravity or by a suitable spring (not shown) a solenoid 93 being provided for actuating the movable member 64, and a solenoid 94 being provided for actuating the movable member 16.

While the current coming from the leads |4, |5 and I6 may be used for energizing the circuits controlled by and through the push-button unit, in cases where high voltage is used it is desirable that the control circuits receive a lower voltage. In such cases a transformer 05 is employed. The primary winding 96 of the transformer receives its current from points 23 and 24 of the contactor or from the jumpers 26 and 21 connecting these points to the points and 2|. Current from the secondary winding |00 of the transformer is connected to the push-button unit |3 and 'to the other parts of the control by control and directional circuits to be hereinafter described.

This push-button unit |3 comprises two push buttons |0| and |02. The button |0| is so connected, as hereinafter described, that when actuated the hoist will elevate the load. The button |02 is likewise so connected that when it is depressed it will actuate the hoist in a lowering direction. The button |0| is mounted upon a reciprocating member |03, carrying switch contact arms |04 and |05. The button |02 is carried by a reciprocating member |06, having switch contact arms ||0 and Since my invention contemplates a two-speed operation of the hoist motor, each button is designed to be depressed part way only for the slowspeed operation, a further depression being given for the fast-speed operation. A number of stationary contact points are provided on the unit for engagement with the switch contact arms. The stationary points H2 and H3 are engagable by the switch contact arm |04, and stationary points ||4 and ||5 are also provided on the unit for engagement by the switch contact arm |05. Stationary points ||B and ||1 are also provided for engagement by the switch contact arm ||0 and stationary points |20 and |2| are likewise provided for engagement by the switch contact arm As shown in the drawings, stationary points ||2 and ||1 are connected together by means of a jumper |22, points ||3 and ||6 are connected together by means of a jumper |23, and stationary points ||5 and |20 are connected together by means of a jumper |24, for reasons to be hereinafter described.

In carrying out my invention, it is most important that certain circuits be established before others are energized. For instance, when rst operating the hoist equipped with my invention, it is desirable that the slow-speed motor circuit be closed synchronously with or before the hoistingor lowering motor circuit is energized for the reason that the magnetic brake is connected in the hoisting and lowering circuits and will be energized before the motor is energized if the slow-speed motor circuit is not first energized, with the result that the magnetic brake will be released and thereby allow the load to lower without control. As shown in the drawings, it is, therefore, desirable that the stationary points ||2 and ||1, controlling the slow-speed motor circuit, be connected to the points ||3 or IIB before these last-mentioned points are connected to the hoisting or lowering points ||4 or |2|, To accomplish this result the ends of the switch arms |04 and ||0 which engage the points ||2 and ||1 are offset, as shown in the drawings, whereby they will first come in contact with these co-acting points before the opposite ends of these arms contact their co-acting points or before one end of either of the arms |05 and comes in contact with its co-acting point, thus assuring that there will always be a sequential engagement of points when either of the buttons |0| or |02 are rst depressed.

Furthermore, I have discovered that it is advantageous and very desirable to prepare the control circuit which controls the fast-speed operation of the hoist before the control circuit which controls the slow-speed operation is interrupted, which controls the slow-speed operation is interrupted. This is accomplished by providing a relatively long leg |25 on the switch arm |04, whereby this arm will remain in contact with the point ||2 until the leg |20 of this switch arm contacts the point ||5. An elongated leg |30 is provided on the switch arm ||0 for prolonged Contact with stationary point ||1 or until such time as the leg |3| of the switch arm makes contact with the stationary point |20. The switch arm |05 is provided with an elongated leg |21 which makes contact with the stationary point |4 following contact of the switch arm |04 with the point-I ||2, and this leg is of suicient length to maintain its contact with the point ||4 throughout the remaining travel ci the button.

In similar manner the switch arm is provided with an elongated leg |32 which makes contact with the stationary point |2| following contact of the leg |30 of switch arm ||0 with stationary point H1. This leg is of suicient length to maintain contact with the point |2| throughout the remaining movement of the button. The switch arm |04 is'provided with an elongatedleg |33 which makes contact with the stationary A the contactors I and are placed within a suitably inclosed and protected housing formed on the hoist, and the push-button unit I3 is suspended from the hoist within reach of the operator. The motor, represented at |2, is, of course, inclosed within the hoist casing and the magnetic brake |35 is, as is well-known, a. standard part of the motor and serves to prevent the motor from rotating when no current is flowing therethrough.

'Ihe hoisting group of points 30, 3| and 32 of the contactor I I are connected, respectively, to the lowering group of points 34, 33 and 35 of this contactor by means of jumpers |36, |31, and |38, respectively. The points 30, 3| and 32 of the hoisting group are likewise connected, respectively to points 10, 12 and 14 by means of leads |82, |83 and |84, respectively. Jumpers 86, 81 and 88 connect the points 10 and 51, 12 and 6|,

' and 14 and 63, respectively, of the speed-determining contactor I0.

Points |40, |4| and |42 on the motor I2 represent the terminals of the slow-speed winding, and these terminals are connected, respectively, to the slow-speed-points 56, 60 and 62 of the contactor I0 by means of leads |43, |44 and |45, respectively, and form parts of the motor circuits. Points |50, |5| and |52 on the motor represent the terminals of the fast-speed winding thereof, and these terminals are connected to the fastspeed points 1|, 13 and 15 of contactor I0 by means of leads |53, |54 and |55, respectively, and form parts of the motor circuits.

The magnetic brake represented at |35 receives its current from lowering points 34 and 35 of the contactor and the winding of the brake is connected to these points by leads |51 and |56, respectively.

One side of the solenoid 54 of the hoisting group is connected to the point 5| of the lowering group by means of a lead |60, and the other side of this solenoid is connected to a common n terminal point |62 by means of lead |6I. The solenoid 55 of the lowering group has one end connected to the point 41 of the hoisting group by means of a lead |63, and the other side of this solenoid is connected to the common terminal |62 by means oflead |64. The connections just described form parts of the directional circuits of my control. The solenoid 94 of the fast-speed group of contactor l0 has one side connected to the point 84 of the slow-speed group by means of a lead |65, and the other side of the solenoid is connected to a common terminal point |66 by means of a lead |61. The solenoid 93 of the slowspeed group has one of its sides connected to the point 90 of the fast-speed group by means of a lead |10, and the other side of this solenoid is' connected to the common terminal |66 by means of a lead |1|. The common terminal point |66 is connected to the common terminal point |62 by means of a lead |12. The solenoids 93 and 94 and the connections just above described form parts of the speed control circuits of my invention.

One side of the secondary winding |00 of the transformer is connected to the common terminal |62 by means of a lead |13. The other side of the secondary winding of the transformer is connected to the stationary contact point ||3 of the push-button unit I3 by means of the lead |14. Current is also conducted to the point ||6 by means of the jumper |23. The stationary point 4 of the push-button unit is connected to the point 52 of the lowering group of contactor by means of a lead |15. The stationary point |2| of the unit is connected to the terminal point 46 of the hoisting group of the contactor by means of a, lead |16. Both of the leads |15 and |16 form parts of the directional circuits. The stationary points |20 and ||5 of said unit are connected to the stationary point 83 of the slowspeed group of the contactor I0 by means of a lead forming part of the slow-speed control circuit. The .stationary points ||2 and ||1 (through the jumper |22) are connected to the point 9| of the fast-speed group by means of a lead |8I, forming part of the fast-speed control circuit.

In the operation of a hoist equipped with my invention, when it is desired, for instance, to elevate a load carried by the hoist, the button |0| of the push-button unit I3 will be operated. Since it is desirable to operate the hoist first at a slow speed,'the button |0| will be depressed only part way. In this position the contact switch arms |04 and |05 will have been moved to the positions shown in Fig. 2. Because of the offset arrangement of the upper end of the arm |04, this arm will contact with the point ||2 before the lower end of the arm contacts with the point I3,- and also before the leg |21 of the switch arm |05 engages contact point |I4, thereby closing one of the slow-speed control circuits. This obviates the possibility of releasing the magnetic brake before current is passed to the electric motor |2. If, for instance, point ||4 is connected to point 3 before point ||2 is connected thereto, current will flow from contact point ||4 over lead |15 of the directional circuit to the normally-closed points 52 and 5| oi the lowering group and through the solenoid 54 of the hoisting group thereby actuating the movable member 36 thereof, and closing points 20-30, 2|-3|, and 22-32 through arms 40, 4| and 42, respectively. Since the magnetic brake |35 is energized through leads |36 and |38, and since these leads are connected to points 30 and 32, current will pass to and through the winding of the magnetic brake and thereby release the brake before the motor is energized, thus allowing any load carried by the hoist to overhaul the motor.

In accordance with my invention, however when the button |08 of the push-button unit is operated, the switch arm |04 will contact point ||2 before it contacts point ||3 and before the switch arm |05 contacts point I I4, thus establishing one of the slow-speed control circuits. Further movement of the arm |04 will connect point I |3 with point ||2 and current will be supplied by lead |14 will be conducted to point I|2 and thence over jumper |22 to lead |8| of the control circuit and to the stationary point 9| of the fast-speed group. Since the arm 92 normally connects the point 9| to the co-acting point 98, current will ow in the control circuit through the arm 92 to point 90 and over lead |10 to solenoid 93, returning over lead |1| to the common point |66 and thence over lead |12 to the. common point |62, and to the other side of the secondary winding |00 of the transformer over lead |13.

When solenoid 93 is energized, the movable member/64 will close stationary points 56--51, 60-6|, and 62--63 through the co-acting arms 65, 66 and 61, respectively. Immediately after the slowspeed control circuit has been prepared as just above described, the leg |21 of the switch arm will make contact with the point |I4. Current will now flow from live point ||3 over lead to the stationary point 52 of the lowering group, across arm 53 to point 5| and thence over lead |60 to the solenoid 54, returning over lead |6| to the common point |62 and thence to the other side of the secondary winding |00 of the transformer, thus establishing the hoisting directional circuit. When solenoid 54 of the hoisting group is energized, the movable member 36 thereof will move arms 40, 4| and 42 into engagement with the points -30, 2|3|, and 22-32 thereof, respectively. Since points 20, 2| and 22 are energized from a suitable source of current over leads I4, I5 and I6, current will now pass from points 30, 3| and 32 over leads |82, |83 and |84, respectively, to the stationary points 51, 6| and 63 of the slow-speed group through the jumpers 86, 81 and 88, respectively. Since the slow-speed control circuithas been initially prepared by the actuation of the movable member 64, current will flow from points 51, 6| and 63 over contact arms 65, 65 and 61, respectively, to points 5G, 60 and 62, respectively, and thence over leads |43, |44 and |45, respectively, to the slow-speed winding terminals |40, |4| and |42,

respectively, of the motor I2 thereby completing the slow-speed hoisting motor circuit.

If it is now desired to operate the hoist at the maximum speed in the same direction, the button |0| is pushed inwardly to the limit of its travel which will bring the points and arms to the relative position shown in Fig. 3 of the drawings. Current will be conducted over the high-speed control circuit from point ||3 to point ||5 over jumper |24 and lead |80 to the stationary point 83 of the slow-speed group ready to cause the solenoid 94 to be energized just as soon as the points 83-84 are permitted to close through the arm 85 by the interruption of current through the lslow-speed solenoid 93. This will occur just as soon as the leg |25 of the switch arm |04 has moved out of contact with the point l2. This allows the movable member 64 of the slow-speed group to return to the position shown in the drawings in which position current will be conducted to the fast-speed solenoid 94 over lead |65 and thence to the common point |66 over lead |61. This will establish the fast-speed control circuit and will cause the movable member 16 to be actuated, thereby closing points 10--1|, 12-13, and 14-,15 through the medium of co-acting arms 80, 8| and 82, respectively, thus establishing the fast-speed motor circuit. Current will now flow to the terminals-|50, |5|, and |52 of the fastspeed winding of the motor through the leads |53, |54 and |55 thereby completing the fast-speed hoisting motor circuit for actuating the motor at full speed.

It is Well-known to those skilled in the art that in present-day switches designed for two-speed overhaul the motor. My invention is designed to overcome this condition by so arranging the contact parts of the push-button unit |3 that the fast-speed control circuit will be prepared for energization before the slow-speed control circuit is broken, or `vice versa. As shown in Fig. 3, therefore, and as hereinbefore described, the contact points and the contact arms of the slowspeed and the fast-speed group are so arranged that arm |05 will make contact with point ||5 before the leg |25 of arm |04 has moved out of contact with point H2, thereby preparing the fast-speed control circuit for energizaticn before the slow-speed control circuit is opened and thereby de-energized.

From' the foregoing it will be obvious that when the solenoid 93 of the slow-speed group is energized, the normally-closed points 83 and 84 of this group will be opened. Since current can reach the fast-speed solenoid 94 only through the contacts 83 and 84, it will be seen that the fast-speed control circuit is interlocked against operation while the slow-speed control circuit is energized. When the solenoid 94 in the fastspeed control circuit is energized, movement of the member 16 thereof will draw arm 82 away from points 90 and 3| thereby opening the slowspeed control circuit. In similar manner, when the hoisting directional circuit causes the energization of solenoid 54 of the hoisting group, points 46 and 41 which are normally closed by the arm 50 will be opened, thereby preventing the passage of current through the solenoid 55 of the lowering directional circuit. In like manner, when the lowering directional circuit causes the energization of the solenoid 55 of the lowering group, points 5| and 52, normally closed by the arm 53, will be opened and thus no current can flow to the solenoid`54 in the hoisting directional circuit. Owing to this arrangement, if both buttons |0| and |02 are pushed at the same time one directional circuit will be sure to close before the other, thereby interlocking the latter -directional circuit and making it impossible to cause both hoisting and lowering directional circuits to be energized at the same time.

In addition to the electrical interlock of the directional contactor Il, I provide a mechanical interlock as shown in Figs. 4 and 5. This is to obviate the possibility of both hoisting and lowering motor circuits being closed at the same time by impact in the event that the hoist is jarred against a stationary object. In order to interlock the moving elements of both groups of this contacter, I provide a pivoted interlocking arm |85 which is mounted midway of its length upon a pivot pin carried by the structure of the oontactor. The4 movable elements 36 and 31 of the hoisting and lowering groups are represented in these figures, and each of them carries a cross member |9| which contacts with the opposite upturned ends |92 of the interlocking arm. The parts are so proportioned that when one of the movable elements is depressed by means of its co-acting solenoid the other element will be prevented from being depressed by mchanical means. Should the forc'e of impact be sulcient to overcome the strength of the acting solenoid, both movable elements will be held in inoperative position by contactl with the upwardly-turned ends of the interlocking arm.

Obviously, when it is desired to lower the load, the lowering button |02 is actuated which, through the medium of the contact arms ||0 and and the stationary contact points H6,

' tion to points 5| and 52,

, contact is first made by II1, |20 and I2I will establish the slow-speed and fast-speed control circuits and also the lowering directional and motor circuits thereby causing the `motor to operate in the lowering direction at either speed.

When the button |02 is depressed, the end of the arm having the leg |30 will first contact with point II 1, and immediately thereafter the opposite end of this arm will contact point IIIi. This will cause the slow-speed control circuit to be energized and the lowering directional circuit to be also energized when the leg |32 of arm III contacts point 2| by current owing over lead |16 to the lowering solenoid 55 through lead |63 and through points 46-41 and connecting arm 50 of the hoisting group, current returning to the secondary winding |00 of the transformer by means oi lead I 64. It will be clear that when solenoid 55 is energized, arm 53 will be moved out of its normally closed relawhereby the hoisting solenoid 54, and, therefore, the hoisting directional circuit will be locked against energization. As in the hoisting of the load, hereinbefore described, when the button is fully depressed for fast-speed lowering movement, the leg I3I of arm |II will contactl point |20 and by means of lead |80 cause the energization of the fast-speed control circuit and solenoid 94, immediately following the de-energlzation of the slow-speed control circuit by the opening of the contact |I6, as hereinbefore clearly set forth in connection with the hoisting movement.

While I have shown and describedthe contact arms |04 and ||0 as having offset portions in order that contact with point |I2 will be made before contact with point I3 is made, or contact with point II'I be made before contact with IIB, the legs |21 and |32 of the arms |05 and III respectively could be shortened or the arms |04 and |I0 may be straight and the points |I2 and I|3 and points I|`| and IIE so offset as to bring about the same results. Furthermore, while I have stated that it is desirable that contact I I2 be made with contact I I3 and contact I Il be made with contact I6 before contact is made with point Ill or point 2| respectively, in order to prevent the energization o1' the magnetic brake before the motor is energized, it; is obvious that the same results may be accomplished if the switch parts are so designed that the points II2 and Ill before contact is made with point II3 or contact is made by the Points |I1 and |2| before contact I I6 is made. These, and other modifications of the details herein shown and described may be made without departing from the spirit of my invention or the scope of the appended claims, and I would not, therefore, wish to be limited to the exact embodiment herein shown and described. K

Having thus described my invention, what I claim is:

1. A control for electric hoists, comprising a contactor having a hoisting motor circuit and an independent lowering circuit, selector means having two independently operable contact-making elements for selecting the desired circuit, and interlocking means carried by said contactor for preventing the energization of both motor circuits simultaneously.

2. A control for reversible electric hoists, comprising a contactor having a hoisting group of contacts for one motor circuit and a lowering group of contacts for another motor circuit, a

directional circuit for each group of contacts luding selector means having contact elemenA operable independently of the contact elements of the other circuit for energizing the respecm tive directional circuits, and contact means included for each directional circuit operable upon the closing of such circuit for opening the directional circuit of the other group and thereby preventing actuation of the other motor circuit.

3. An electric hoist having a hoisting motor. circuit with normally open switch means thereinand a lowering motor circuit with normally open switch means therein, a directional circuit foi each of the directional motor circuits, each direc-- tional circuit including an electromagnetic means operable for closing the contacts of the respectivev motor circuits, and normally closed contact means included in each directional ciru cuit and adapted to be opened by the electro magnetic means of the companion directional circuit for preventing the simultaneous closing of both motor circuits.

4. An electric hoist, having a motor provides with a slow-speed circuit and a fast-speed cir cuit a contactor having a slow-speed group of contacts and a fast-speed group of contacts. selector means for actuating said slow-speed group and said fast-speed group in sequencel` and contact means carried by each group of con`v tacts and operable by the actuation of the selectorl means for opening the circuit governed by the companion group of contacts by and during the closing of the selected group of contacts.

5. An electric hoist, having' a motor provided with a slow-speed circuit and a fast-speed cir-- cuit, a contactor having a slow-speed group of contacts and a fast-speed group of contacts, selector means for actuating said slow-speci? group and said fast-speed group in sequence, said actuating means having contacts so ar ranged that the fast-speed circuit is preparer?, for energization before slow-speed circuit broken.

6. An electric hoist, having a motor provided with a slow-speed circuit and a fast-speed cir cuit, a contactor having a slow-speed group ci contacts and a fast-speed group of contacts, selector means for compelling the energization of the slow-speed circuit and the fast-speed cir cuit in succession, electro-magnetic means for closing each group of contacts, and switch means in circuit with each electro-magnetic means and operable upon the closing of the companion elec" tro-magnetic means for interrupting its circuit and preventing the operation of both electromagnetic means simultaneously.

7. An electric hoist, having a motor provided with a slow-speed Winding connected in a slowspeed circuit, and a separate independent fastspeed winding connected in a fast-speed circuit, a contactor having separate groups of contact means governing the supply of current to the speed-responsive circuits, power means for supplying current to said contactor, and manuallyoperated switch means for causing the initial energization of the slow-speed circuit and for maintaining said energization until the fastspeed circuit is prepared for energization by and through the opening of the slow-speed circuit.

3. An electric hoist having a two-speed reversible motor with a hoisting .circuit and a lowering circuit, a directional switch in each motor circuit operable for selectively closing its circuit, a slow-speed switch and a fast-speed switch adapted for being successively interposed Contact point common in the selected motor circuit, a directional circuit for each directional switch including means operable to close such direction switch, a separate control circuit for each speed-determining switch including means operable to close such speed switch, selector means operable initially to close the slow-speed switch control circuit and a directional switch control circuit to start the motor and then to close the fast-speed switch control circuit, and means in each speed switch control circuit operable upon the closing thereof lor disposing the control circuit for the other speed switch against being closed simultaneously and thereby compel such successive order of interposing the two speed switches in the selected motor circuit.

9. In a control for electric hoists, the combination with a two-speed motor, two motor circuits, and two speed-determining control circuits connectable in either motor circuit, of a control circuit for each motor circuit, electromagnetic means in each control circuit, a pushbutton unit having a hoisting group of contact members and a lowering group of contact members, comprising a supply contact point cornmon to both groups of members, a slow-speed to both groups, a fastspeed contact point common to both groups, a hoisting contact point, and an independent lowering contact point, said unit having movable contact arms engagable with said contact points, the contact arms being so proportioned and positioned in relation to the respective contact points that the fast-speed control circuit will be prepared for energization before the slow-speed control circuit is opened.

10. In an electric hoist wherein a motor has two directional control circuits, two speeddetermining control circuits, an electro-magnetic brake energized by either of said speed-determining circuits, and means are provided for closing each of said control circuits, the combination with a manual switch having a set of contacts for each directional circuit and a set of contacts for each speed-determining circuit, the speeddetermining circuits being common to each directional circuit, means for closing one speeddetermining circuit and one directional circuit with the arrangement being such that the speeddetermining circuit will be closed through its contacts by the time the directional circuit is closed, and means for successively closing the speed-determining circuits with the arrangement beingsuch that the initially closed set of contacts ofsuch circuit are not opened until after the closing of the set of contacts controlling the other circuit, whereby said brake will be applied until the motor is energized.

l1. A push-button unit for electric hoists, such hoists having two motor circuits, and two speed-determining control circuits, said unit having contact members so proportioned and arranged that the contact members governing one control circuit shall overlap the contact members governing the other control circuit, whereby one control circuit shall be prepared for energization before the other speed-determining circuit is opened.

l2. A push-button unit for electric hoists, such hoists having two motor circuits, and two speed-determining control circuits, said unit having contact members so relatively positioned that one of said control circuits shall be energized by the time either of the directional circuits is energized, and said contact members being so proportioned and arranged that the contact members governing one control circuit shall overlap the contact members governing the other control circuit, whereby one control circuit shall be prepared for energization before the other control circuit is opened.

13. A manual switch for interlocking contact circuits of the slow-speed and fast-speed circuits of a two-speed electric hoist,- said switch comprising a iixed contact for each interlocking control circuit, and movable contact means for successively establishing electrical connection with each fixed contact and maintaining such connection with the initially engagcable contact f until after connection is established with the other contact, whereby to prevent the opening of one circuit before the other circuit is prepared for energization by and through the opening of the initially-'energized circuit.

14. An electric hoist having a hoisting motor circuit with a group of normally open contacts therein and a lowering motor circuit with a group of normally open contacts therein, a directional circuit for each motor circuit, each directional circuit including electromagnetic means operable for closing the contacts of the respective motor circuits, switch contact means in each directional circuit and operable upon closing the latter to open the electro-magnetic means of the companion directional circuit for preventing the simultaneous closing of both motor circuits, a slow-speed group of normally open contacts adapted to be arranged in series with either group of motor circuit contacts, a fast-speed group of normally open contacts adapted to be' arranged in series with either group of motor contacts, and selector means for selectively closing either group of speed contacts.

l5. In a control for electric hoists, the combination with a two-speed motor, two motor circuits, and two groups of speed-determining normally open contacts selectively connectable in either motor circuit, of a control circuit for closing each group of contacts, electro-magnetic means in each control circuit, and a push-button unit having contact members connected to a suitable source of electrical supply and to each of said control circuits, said contact members being so relatively positioned that one of said groups of speed-determining contacts should be closed by the time the selected motor circuit is energized.

16. A control for electric hoists, having a motor provided with a slow-speed motor circuit and a fast-speed motor circuit, comprising a contactor 'having a slow-speed group of contacts and a fast-speed group of contacts for connection respectively to said slow-speed and fastspeed motor circuits, a slow-speed control circuit and a fast-speed control circuit, a selector unit connected in said control circuits for causing said slow-speed and said fast-speed control circuits to be energized in sequence, normally closed contact means connected in said control circuits for opening each control circuit when the companion circuit is closed, and said selector unit having contact means for preparing the open control circuit for energization upon and through the opening of the closed control circuit.

17. An electric hoist having a slow-speed motor circuit and a fast-speed motor circuit, each circuit including normally open contact means movable to a circuit closing position from a normally open position, electric means for so movmotor circ'uits simultaneously,

switch means lng each contact means to a circuit closing position, normally closed contact means in circuit with each moving means and each operable to an open position by the companion moving means when the normally open contact means of the companion motor are moved to a circuit closing position whereby to prevent the closing of both and manual means in series with each normally closed contact means for cooperating therewith to close the circuit of the electric means.

18. An electric hoistl having a reversible motor, an up motor circuit for the motor, a down motor circuit for the motor, normally open contact means in each circuit, a directional circuit for each contact means including electric means for closing its associated contact means, manual means for selectively closing either` directional circuit, each directional circuit also including a normally closed switch in the companion directional circuit and openablelby and during the operation of the electric means of the selected directional circuit whereby to prevent the manual closing of both motor circuits simultaneously, slow-speed control means, fast-speed control means, manually operable means for motor circuit, automatic means to close the slowspeed switch means and separate automatic means to close the fast-speed switch means, manually controlled slow and fast switch means in circuit with the automatic means for the two said speed switch means respectively, the arrangement being such that the manually conselectively connecting either speed control means the motor for hoisting and lowering, normally open slow-speed switch means and fast-speed switch means selectively connectible in the selected motor circuit, automatic means to close the slow-speed switch means and separate automatic means to close the fast-speed switch means, and manually controlled slow and fast in circuit with the automatic means for the two said-speed switch means respectively, the arrangement being such that the manually controlled slow switch means will be initially closed followed bythe closing of the others of the aforementioned manually controlled switch means.

20. A hoist comprising a reversible motor, slow and fast motor circuits therefor, switch means manually controlled to selectively actuate the motor for hoisting-and lowering, normally open slow-speed switch means and fast-speed switch means selectively connectible in the selected trolled slow switch means will be initially closed followed by the closing of the others of the afore-` mentioned manually controlled switch means, and normally closed protective switch means in each of the speed circuits of the manually controlled slow and fast switch means, the normally closed protective switch means of each speed circuit being opened by the automatic means of the companion speed circuit when such automatic means is functioning to close its associated normally open speed switch means, whereby the speed circuits are prevented from being simultaneously closed.

21. A hoist comprising a reversible motor, slow and fast motor circuits therefor, switch means manually controlled to selectively actuate the motor for hoisting and lowering, normally open slow-speed switch means and fast-speed switch means selectively connectible in the selected motor circuit, automatic means to close the slow-speed switch means and separate automatic means to close the fast-speed switch means, manually controlled slow and fast switch means in circuit withvthe automatic means for the two said speed switch means respectively, the arrangement being such that the manually controlled slow switch means will be initially closed followed by the closing of the others of the aforementioned manually controlled switch means, and normally closed protective switch means in each of the speed circuits of the manually controlled slow and fast switch means, the normally closed protective switch means of each speed circuit being opened by the automatic means of the. companion speed circuit when such automatic means is functioning to close its associated normally open speed switch means, whereby the speed circuits are prevented from being simultaneously closed, said manually closed slow switch means being manually open subsequent to the closing of the manually controlled fast switch means while retaining the latter closed whereby to render the associated slow speed automatic means inoperative and to restore the slow-speed switch means and its controlled protective switch means respectively to their normally open and normally closed positions, and thereby effect the actuation of the companion fast-speed automatic means.

CHARLES J. MANNEY.

CERTI F'I CATE OF CO RREC TI ON PatentV No. 2,352,590. october 19,- 19H5.

CHARLES JQ nANNEy.

It is hereby certified that error appears in the printed specification of th'e above numbered patent requiring correction as follows: Page 2*, second column, lines 11.8 andli9, strike out the words and comma "which controle the slow-speed operation is interrupted; page 5, second column, line 6, c'laim 2, for for before "each" read --in; and that the said Letters Patent should be read with this correcti on therein thatithe game may conform to the record of lthe case in the Patent Offie.

signed' and sealed this 21st day of-December, A. D. 191g.

Henry Van Arsdale I l) Acting Commissioner of Patents.

Sea

- CERTIFICATE oF CORRECTION. l .t Patenpno. 2,552,590. october 19, 19M.

CHARLES J. MANNEY.

It is hereby certified that error appears in the prntedspecification of th'e'above numbered patent requiring correction es follows: Page 2, second colimm, lneslB andh9, strike out the words and comme. "which controle the slow-speed `operation is nterrupted,"; page 5, second column, line 6, elaim 2, for "for" before "each" read -1n; `and that the said Letters Patent should be read with this correct on therein thatthe game may conform to the record of the case in the Patent Offioe.

Sigled'and sealed this 21st day of-Dec'ember, A. D. 191;.5.

Henry Van Arsdale,

tin Commissioner of Patents. (S951) Ac g A 

